On Mon, May 18, 2020 at 4:53 PM Thomas Gleixner <[email protected]> wrote: > > Andy Lutomirski <[email protected]> writes: > > Actually, I revoke my ack. Can you make one of two changes: > > > > Option A: Add an assertion to run_on_irqstack to verify that irq_count > > was -1 at the beginning? I suppose this also means you could just > > explicitly write 0 instead of adding and subtracting. > > > > Option B: Make run_on_irqstack() just call the function on the current > > stack if we're already on the irq stack. > > > > Right now, it's too easy to mess up and not verify the right > > precondition before calling run_on_irqstack(). > > > > If you choose A, perhaps add a helper to do the if(irq_needs_irqstack) > > dance so that users can just do: > > > > run_on_irqstack_if_needed(...); > > > > instead of checking everything themselves. > > I'll have a look tomorrow morning with brain awake.
Also, reading more of the series, I suspect that asm_call_on_stack is logically in the wrong section or that the noinstr stuff is otherwise not quite right. I think that objtool should not accept run_on_irqstack() from noinstr code. See followups on patch 10.
